'Arrow' Season 5, Episode 23: Deathstroke returns to help Oliver in the season finale

Wednesday night's episode of Arrowdid about everything it could to pump up fans for what is sure to be an action-packed season finale. Despite surrendering to Oliver in episode 21, with the help of returning characters like Talia al Ghul, Black Siren and Artemis, Chase is able to kidnap one Team Arrow member after another.

Now, with all of Oliver's friends and family on Lian Yu, the Green Arrow will turn to some unlikely sources for help defeating Prometheus once and for all. Not only will Oliver recruit former League of Assassins members Nyssa al Ghul and Malcolm Merlyn, but he will seek help from one of his greatest adversaries: Slade Wilson, aka Deathstroke.

Deathstroke's return was rumored, and then confirmed, in April, but that doesn't make seeing one of Arrow's greatest villains back on the series any less fun. Of course, this time it appears he will be fighting alongside the Green Arrow. The setting for this fight, Lian Yu, is definitely appropriate, as the series began on the island, and now, five years later, Oliver will return there as Arrow largely abandons the flashback narrative going forward.

Black Siren is just one of several characters who will fight in the season finale.Source: Katie Yu/The CW

Arrow's season five finale, titled "Lian Yu," will also feature the return of Digger Harkness, aka Captain Boomerang, who has made appearances on both The Flash and Arrow, and is currently imprisoned in the same island jail as Deathstroke. All things considered, it certainly sounds like Arrow is pulling out the big guns for its season-ender.

Want to know some more? Check out the official synopsis, via Spoiler TV, for the season finale below:

The battle between Oliver and Adrian Chase culminates in a final epic battle on Lian Yu. After recent events, Oliver decides to recruit a group of unlikely allies — Slade, Nyssa, Merlyn and Digger Harkness — to defeat Chase. However, Chase has his own army — Black Siren, Evelyn Sharp and Talia al Ghul — and the forces collide in an explosive season finale.